The purpose of the large animal core will be to coordinate and facilitate the in utero gene therapy protocols of all investigators. The personnel supported by this core have extensive experience in general sheep husbandry and in specific aspects of the sheep as an experimental model. This includes extensive experience in survival surgical manipulation of the fetus, with implantation of chronically indwelling fetal catheters and blood flow probes. In the past year we have also developed expertise in surgical approach to 50 day fetuses. The services that the core will provide are: 1. Coordination of all aspects of animal care. 2. Performance of all Surgical Procedures. 3. Post operative Care of transplanted animals. 4. Supervising lambing procedures. The demands on the core as proposed in this grant (12 sheep per year) are well within the capabilities of present personnel and facilities. Therefore, prioritization will involve only the scheduling of surgical time for cell transplantation.